Coordination chemistry of new chiral P,N ferrocenyl ligands with half-sandwich ruthenium(II), rhodium(III), and iridium(III) complexes

Article abstract of DOI:10.1021/om300738q

The new half-sandwich ruthenium(II), rhodium(III), and iridium(III) complexes (p-cymene)RuCl₂L and Cp*MCl₂L (M = Rh, Ir), where L is a planar chiral ferrocenyl tosylamine-phosphine ligand {1,2-(TosNRCH₂)(PPh₂)C₅H₃}FeCp (R = H, Me) coordinated in a monodentate fashion (κ¹P), have been synthesized and fully characterized both in solution (multinuclear NMR, mass spectrometry) and in the solid state (X-ray analysis on single crystals). Intra- and intermolecular N-H...Cl bonds were observed. Variable-temperature NMR shows an equilibrium between different structures, which have been discussed with the help of DFT calculations. Addition of triethylamine to the complexes with R = H allows removing the tosylamide acidic hydrogen, giving rise to a ferrocenyl amidophosphine ligand coordinated in a bidentate fashion (κ²P,N). All complexes have been fully characterized by multinuclear NMR and mass spectrometry. The structure of the iridium complex, determined by X-ray diffraction, shows a planar nitrogen atom and a stable metal-centered chirality. Only the most stable diastereoisomer, according to DFT calculations, has been observed. A number of these complexes were assessed in the catalytic transfer hydrogenation and asymmetric transfer hydrogenation of acetophenone.

Full text of DOI:10.1021/om300738q

Article
pubs.acs.org/Organometallics
Coordination Chemistry of New Chiral P,N Ferrocenyl Ligands with
Half-Sandwich Ruthenium(II), Rhodium(III), and Iridium(III)
Complexes
§
†,‡
Muh-Mei Wei,†,‡ Max Garcıa-Melchor, Jean-Claude Daran, Catherine Audin,†,‡,∥ Agustí Lledos,§
́
́
Rinaldo Poli,†,‡,# Eric Deydier,*,†,‡,∥ and Eric Manoury*,†,‡
†CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4, France
‡UPS, INPT, Universite
́
de Toulouse, F-31077 Toulouse Cedex 4, France
̀
oma de Barcelona, 08193 Cerdanyola del Valles, Spain
§
́
Departament de Quımica, Edifici C.n, Universitat Auton
̀
∥Dep
́
artement de Chimie, IUT A Paul Sabatier, avenue Georges Pompidou, BP 258, F-81104 Castres Cedex, France
#Institut Universitaire de France, 103 boulevard Saint-Michel, 75005 Paris, France
S
* Supporting Information
ABSTRACT: The new half-sandwich ruthenium(II),
rhodium(III), and iridium(III) complexes (p-cymene)RuCl2L
and Cp*MCl2L (M = Rh, Ir), where L is a planar chiral
ferrocenyl tosylamine-phosphine ligand {1,2-(TosNRCH2)-
(PPh2)C5H3}FeCp (R = H, Me) coordinated in a monodentate
fashion (κ1P), have been synthesized and fully characterized
both in solution (multinuclear NMR, mass spectrometry) and
in the solid state (X-ray analysis on single crystals). Intra- and
intermolecular N−H···Cl bonds were observed. Variable-temperature NMR shows an equilibrium between different structures,
which have been discussed with the help of DFT calculations. Addition of triethylamine to the complexes with R = H allows
removing the tosylamide acidic hydrogen, giving rise to a ferrocenyl amidophosphine ligand coordinated in a bidentate fashion
(κ2P,N). All complexes have been fully characterized by multinuclear NMR and mass spectrometry. The structure of the iridium
complex, determined by X-ray diffraction, shows a planar nitrogen atom and a stable metal-centered chirality. Only the most
stable diastereoisomer, according to DFT calculations, has been observed. A number of these complexes were assessed in the
catalytic transfer hydrogenation and asymmetric transfer hydrogenation of acetophenone.
Hemilability is of particular interest in catalysis, as these ligands
allow the formation of reactive sites while improving the
catalyst stability. However, the ability of chiral ligands to
undergo rapid association/dissociation processes may be a
problem in asymmetric catalysis, when the reaction selectivity is
controlled by the metal stereochemistry. This is particularly
true when the metal is an additional center of chirality in the
ligand-associated form. Indeed, reaction of a pure R configured
bidentate ligand (RL) will give the two diastereoisomers RLRM
and RLSM and the selective formation of a specific
diastereoisomer may be a challenge.5,6
One family of such chiral-at-metal complexes are the half-
sandwich complexes of ruthenium, rhodium, and iridium, which
have found efficient applications for instance in asymmetric
transfer hydrogenation (ATH). Ligands used for this reaction
are mainly amino alcohols or bidentate N,N ligands bearing a
NH bond which is involved in the hydrogen transfer
mechanism according to Noyori’s proposal.7−11 However, a
few research groups have reported non-“NH” P,N ligands active
INTRODUCTION
■
Homogenous asymmetric catalysis by transition metals has
received considerable attention over the last few decades.
Numerous chiral ligands and complexes allowing high-
efficiency reactions have been reported. In this area, chiral
phosphines have played a significant role.1,2 The possibility of
easy modification of their electronic and steric properties by a
judicious choice of substituents has proven extremely useful to
successfully optimize catalytic reactions. In recent years, the use
of diphosphine ligands (P,P ligands) and monophosphine
ligands containing an additional donor atom (P,X ligands) with
different “hard” and “soft” character (according to Pearson’s
HSAB concept) have been widely investigated. Among the
numerous P,X ligands reported to date, chiral bidentate P,N
ligands bearing a soft phosphine and a hard nitrogen provide
interesting electronic and coordinating properties.3 Their
coordination with transition metals affords efficient catalysts
for numerous asymmetric applications such as hydroformyla-
tion and hydrosilylation.4
The nature of the nitrogen atom (sp3 or sp2), the electronic
effects of its substituents (alkyl, aryl), and their steric hindrance
allow easy modulation of the nitrogen donor atom lability.
Received: August 2, 2012
© XXXX American Chemical Society
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in transfer hydrogenation (TH). Among them, a few ferrocenyl
phosphines have proven to be very efficient. Indeed, Stradiotto
et al. recently reported ee’s up to 95% in the ATH of sterically
hindered ketones under mild conditions (40 °C) using a
P,N(sp3) ligand bearing a NMe2 group and [IrCl(COD)]2 as a
metal precursor (Chart 1, ligand 1).12 A similar efficiency was
solution of 3 (Scheme 1) under the reaction conditions
previously optimized for the synthesis of ferrocenyl phos-
phine.30,31 After purification by flash chromatography on silica
gel, compounds 4 and 4a were obtained as yellow powders in
quantitative yields and were fully characterized by mass
spectroscopy and multinuclear NMR.
Compound 4 has been characterized by single-crystal X-ray
diffraction. A view of the molecule is shown in Figure 1, and
Chart 1
also reported using ruthenium catalyst 2 (Chart 1) with a
P,N(sp2) ligand which involves a chiral oxazoline nitrogen atom
donor.13−15 These examples suggest the occurrence of a
different mechanism in transfer hydrogenation, and various
experimental or/and computational studies have been carried
out to better understand the coordination chemistry of P,N
ligands and their role in TH.12,16−20
We have long been interested in the design and the synthesis
of new chiral ferrocenyl ligands for exploring new asymmetric
catalytic reactions or for improving the existing ones.21−26 The
important application of chiral ferrocene ligands in asymmetric
catalysis has been highlighted in recent reviews.27,28 In the
present paper we report the synthesis and coordination
chemistry of a new P,N chiral ferrocenyl ligand, bearing a
TosNR fragment (R = H, Me), with ruthenium, rhodium, and
iridium half-sandwich complexes. The facile H removal allows
switching from a P-amino to a stronger P-amido donor. The
ligand coordination and lability and the stereochemistry of the
resulting complexes will be explored through both experimental
and computational work. A preliminary evaluation of these
complexes in ATH and asymmetric hydrogenation (AH) will
also be presented.
Figure 1. Molecular view of compound 4 with the atom labeling
scheme. Ellipsoids are drawn at the 30% probability level.
Table 1. Selected Bond Distances (Å) and Bond Angles
(deg) for Compound 4
Distances
Fe−Ct1
Fe−Ct2
P1−C1
P1−S1
1.6406(7)
1.6521(9)
1.7943(15)
1.9532(5)
1.497(2)
C21−N1
N1−S2
S1−O1
S1−O2
1.466(2)
1.6255(13)
1.4327(12)
1.4276(12)
RESULTS AND DISCUSSION
■
Ligand Synthesis. 2-Thiodiphenylphosphino-
(hydroxymethyl)ferrocene (3) was chosen as starting material
for this work. This compound can be prepared in multigram
quantities and isolated as a racemic mixture or in a pure
enantiomeric form, opening direct access to chiral ligands.29
Moreover, the phosphino function is protected from oxidation
by a sulfur atom, allowing working in air. Ligands 5 and 5a were
prepared in a two-step reaction by successive addition of HBF4
and tosylamide or methyltosylamide to a dichloromethane
C2−C21
Angles
a
Ct1−Fe−Ct2
C21−N1−S2
177.55(7)
C21−N1−H1A
S2−N1−H1A
112.51(14)
109.78(11)
115.78(10)
a
Ct1 and Ct2 are the centroids of the Cp rings.
a
Scheme 1. Synthesis of Ligands 5 and 5a
a
Legend: (i) CH2Cl2, HBF4, H2NSO2(C6H4)CH3 or HNMeSO2(C6H4)CH3; (j) reflux in toluene, P(NMe2)3, overnight.
B
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selected structural parameters are given in Table 1. The sulfur
atom is endo with respect to the Cp ring, being away from the
ring plane by 1.013(3) Å, as observed in related ferrocenyl
derivatives. The two Cp rings are roughly parallel (dihedral
angle of 2.4(1)°) and are nearly eclipsed (twist angle of
1.05(12)°). The nitrogen atom is pyramidal (∑(angles) =
338.0(2)°) and endo with respect to the Cp ring, with the
hydrogen atom pointing toward the sulfur atom S1, resulting in
a intramolecular N−H···S hydrogen bond (Table 2). All bond
lengths and angles in this structure are within the expected
range.
complexes have been fully characterized by multinuclear NMR
and mass spectrometry and by X-ray crystallography.
In all cases, the chloro-bridged dimer was cleaved by the
phosphorus atom coordination while the nitrogen atom
remains uncoordinated, as shown by the X-ray structures.
ORTEP views of the three geometries are presented in Figure
2. All three compounds adopt a roughly similar coordination
environment with the phosphorus atom coordinated to the
metal resulting in a “three-legged piano stool” geometry. A
major difference is the presence of an intramolecular H bond in
the structure of 6, whereas those of compounds 8 and 10
feature an intermolecular H bonding network yielding infinite
chains parallel to the [100] axis (Table 2). Compounds 8 and
10 are isomorphic in the polar P21 space group, whereas 6
Table 2. Hydrogen Bond Parameters for Compounds 4, 6, 8,
and 10
crystallizes as a racemate in the centrosymmetric group P1.
̅
a
a
a
N1−H (Å)
H···X (Å)
N1···X (Å)
N1−H···X (deg)
Examination of selected geometric parameters shows that the
three structures have an essentially identical geometry (Table
3). The main differences are a smaller Cl1−M−Cl2 angle and
greater distances of the N1 and P1 atoms from the ferrocene
Cp ring plane in compound 6. These differences might be
related to the intramolecular N−H···Cl1 hydrogen bond.
Another difference in these structures is that the two Cp
rings in compound 6 are nearly eclipsed with a twist angle of
4.0(2)°, whereas they are staggered in compounds 8 and 10
(Table 3). The hydrogen bond influences the M−Cl distance,
which is significantly longer in each compound relative to that
of the free M−Cl bond. Similar observations were reported by
Cowie et al. for half-sandwich ruthenium complexes bearing a
P-amine ligand.32 The nitrogen atom in the structure of 6 is
essentially planar, with a sum of the angles equal to 359.4(2)°,
whereas a significant degree of pyramidalization is observed in
the structures of compounds 8 and 10 (348.7(3) and
351.1(4)°, respectively). A closer look at Tables 2 and 3
4
0.85
0.78
0.94
0.95
2.45
2.40
2.40
2.42
3.282(1)
3.172(2)
3.253(3)
3.247(4)
167.5
171.9
149.7
146.1
6
8
10
a
X= S (4) or Cl (6, 8, 10).
Desulfurization was achieved with high efficiency using
tris(dimethylamino)phosphine in refluxing toluene for 12 h
under an argon atmosphere. Ligands 5 and 5a were recovered
as yellow solids after flash chromatography (93% and 100%
yields, respectively) and fully characterized by mass spectrom-
etry and multinuclear NMR.
Coordination of Ligand 5. Racemic 5 reacts in dichloro-
methane at room temperature with the half-sandwich
complexes [RuCl(μ-Cl)(η6-p-cymene)]2 and [MCl(μ-Cl)(η5-
Cp*)]2 (M = Rh, Ir) to produce complexes 6, 8, and 10,
respectively, in quantitative yields (Scheme 2). All of these
a
Scheme 2. Synthesis of Complexes 6−8, 8a, and 9−11
a
Legend: (i) CH2Cl2, room temperature, [RuCl2(Cymene)]2, 1 h; (j) CH2Cl2, room temperature, [RhCl2(Cp*)]2, 1 h; (k) CH2Cl2, room
temperature, [IrCl2(Cp*)]2, overnight; (l) NEt3 (5 equiv), room temperature, overnight.
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Figure 2. ORTEP views of compounds 6, 8, 8a, and 10 with the atom labeling scheme. Ellipsoids are drawn at the 30% probability level. For the sake
of clarity, H atoms are not shown, except for the NH atom of compound 6 involved in the intramolecular hydrogen bond.
shows that the N···Cl and N−S lengths in compound 6 are
slightly shorter than in compounds 8 and 10. This result seems
to suggest that the stronger H bond in 6 increases the electron
density on the sp2 nitrogen, which is then partially transferred
to the sulfur atom through a π interaction.
In solution, the phosphorus atom coordination is easily
followed by the downfield shift of the 31P NMR signal. Upon
coordination to the Ru atom in compound 6, the resonance of
the free ligand at δ −24.2 is replaced by a sharp singlet at δ
14.6. The final product possesses two elements of chirality:
namely, the planar chiral ferrocenyl group and the metal atom.
The latter is chiral because of the intramolecular hydrogen
bond that involves one of the two Cl atoms. Thus, two
diastereomeric pairs of enantiomers could in principle be
obtained. The single resonance is presumably resulting from a
rapid interconversion between the two diastereoisomers
through the symmetric intermediate A (Scheme 3).
chemical shift could result from a simple variation of the
medium polarity (dichloromethane is known to have a strongly
temperature dependent dipole moment) and examples where
this phenomenon occurs are common in 31P NMR
spectrometry, the broadening followed by sharpening un-
ambiguously signals the presence of dynamic exchange
phenomena. The single resonance observed at the slow
exchange limit shows that one diastereoisomer is predominant,
with the minor isomer(s) remaining undetected.
For the rhodium and iridium complexes 8 and 10, the
31P{1H} NMR spectra at room temperature gave broad signals
at δ 24.2 and −7.0, respectively. For both complexes, the
resonance further broadens upon cooling without a significant
shift and then decoalesces to yield two signals of unequal
intensity at 253 K for 8 or 233 K for 10 (Figure 3). Further
cooling to 213 K reveals the presence of at least three
compounds. For complex 8, the spectrum at 213 K reveals a
broad doublet at lower field around δ 28.8 (JRh−P = 141 Hz) as
the major component, plus two higher field sharp doublets at δ
In order to probe the possible existence of isomers, variable-
temperature 31P NMR investigations were carried out (Figure
3). Upon cooling, the δ 14.6 signal shifted upfield and
broadened, reaching maximum line width at 213 K, followed by
sharpening and further upfield shifting until a sharp singlet was
obtained at δ 11.3 at 183 K. Whereas a temperature-dependent
20.6 (JRh−P = 144 Hz, intermediate intensity) and 20.4 (JRh−P
=
144 Hz, minor intensity). Complex 10 exibits a similar
behavior, a broad signal (major) being observed around δ
−1.8 plus two higher field sharper singlets at δ −9.0 (minor)
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Table 3. Selected Geometric Parameters (Distances in Å, Angles in deg) for Compounds 6, 8, 8a, and 10
6
8
8a
10
Distances
1.644(2)
1.657(2)
2.3656(8)
1.8295(4)
2.4008(9)
2.4094(8)
1.818(3)
1.500(5)
1.464(4)
1.614(3)
1.429(3)
1.427(3)
0.235(6)
−0.008(6)
−0.595(7)
0.249(8)
Angles
Fe−Ct1
Fe−Ct2
M1−P1
M1−Ct3
M1−Cl1
M1−Cl2
P1−C1
C2−C21
C21−N1
N1−S1
S1−O1
S1−O2
P1···Cp(plane)
C21···Cp(plane)
N1···Cp(plane)
M1···Cp(plane)
1.6502(9)
1.6555(12)
2.3644(5)
1.6973(8)
2.4123(5)
2.4087(5)
1.8085(19)
1.496(3)
1.649(4)
1.653(4)
2.355(2)
1.827(4)
2.388(2)
2.394(2)
1.799(8)
1.515(11)
1.462(11)
1.627(7)
1.440(7)
1.425(7)
0.266(12)
−0.022(15)
0.00(2)
1.643(2)
1.663(2)
2.3375(11)
1.833(2)
2.4059(12)
2.4114(11)
1.808(4)
1.496(6)
1.468(6)
1.615(4)
1.428(4)
1.429(4)
−0.241(7)
0.017(8)
0.595(8)
−0.249(10)
1.457(3)
1.5903(18)
1.4294(17)
1.4307(17)
0.447(3)
−0.015(3)
1.349(4)
2.731(3)
0.212(18)
Ct1−Fe−Ct2
Ct3−M1−Cl1
Ct3−M1−Cl2
Ct3−M1−P1
Cl1−M1−Cl2
Cl1−M1−P1
Cl2−M1−P1
C21−N1−S1
C21−N1−-R1
S1−N1−R1
C2−C21−N1−S1
τ
174.32(5)
123.90(3)
124.98(3)
128.50(3)
87.46(2)
176.03(9)
122.10(6)
119.54(6)
132.69(6)
91.96(3)
93.19(3)
86.51(3)
119.92(24)
118.60(29)
110.20(24)
−135.21(27)
26.6(3)
176.9(2)
119.07(14)
121.74(16)
133.14(16)
92.91(8)
92.19(8)
87.25(7)
118.8(6)
114.9(7)
117.3(7)
−128.9(7)
12.8(6)
175.93(13)
119.84(7)
122.59(7)
133.04(7)
89.28(4)
93.41(4)
86.87(4)
119.9(3)
120.3(4)
110.9(3)
135.8(3)
25.8(4)
91.89(2)
88.09(2)
123.63(15)
120.21(20)
115.59(17)
−130.35(17)
4.0(2)
Scheme 3. Proposed Equilibrium between Two Diastereoisomers of Compound 6
and −10.1 (intermediate). These observations would appear
consistent with the equilibration hypothesis formulated for
compound 6 in Scheme 3. Even though compounds 8 and 10
reveal an intermolecular H bonding in the solid state, their
structure in solution could involve, like that observed for 6 in
the solid state, an intramolecular H bond. Further investigations
of this issue by DFT calculations will be shown later in DFT
Calculations.
and 30.9 (JRhP = 142 Hz) for the rhodium complex 9, and two
singlets at δ −0.9 and −10.1 for the iridium complex 11. The
simultaneous P and N coordination creates a nonlabile chiral
center at the metal atom, giving rise to two possible
diastereoisomers: SL,SM and RL,RM; SL,RM and RL,SM.
Crystallization of 11 from a dichloromethane/hexane
mixture gave crystals suitable for an X-ray diffraction analysis.
A view of this compound is shown in Figure 4. The chelating
P,N ligand and one chlorine atom complete the coordination
sphere of the three-legged piano stool, as observed in related
compounds published in the literature.33−35 The distances and
angles (Table 4) are in the normal range in comparison to the
related compounds. The structure presented corresponds to the
SL,SIr diastereoisomer, but as the space group is centrosym-
metric, the RL,RIr enantiomer is also present within the crystal.
The solid-state 31P{1H} NMR spectrum of the crystals gave
only one signal at δ −7.7, and redissolution of the crystallized
sample in CDCl3 gave back only the signal at δ −10.1,
confirming the selective crystallization of the RL,RIr/SL,SIr
diastereoisomer. Consequently, the other 31P{1H} NMR signal
P-amido Complex Synthesis. Addition of 5 equiv of
triethylamine to dichloromethane solutions of complexes 6, 8,
and 10 yielded the P-amido complexes 7, 9, and 11,
respectively, where the anionic nature of the amido ligand
favors the ligand coordination in a κ2P,N fashion with the
concomitant replacement of a chlorido ligand (Scheme 2). All
of these complexes have been fully characterized by multi-
nuclear NMR and mass spectrometry. Unlike their precursors
1
6, 8, and 10, these complexes present sharp signals in the H
and 31P{1H} NMR spectra. The latter exhibits two signals with
similar intensities: two singlets at δ 18.3 and 26.6 for the
ruthenium complex 7, two doublets at δ 19.6 (JRhP = 147 Hz)
E
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Figure 3. 31P{1H} NMR variable-temperature analysis of compounds 6 (extreme left), 8 (middle left), 10 (middle right), and 8a (extreme right).
The solvent used was CD2Cl2 unless otherwise indicated. The resonance marked with an asterisk in the spectrum of 8a corresponds to an impurity
resulting from oxidation.
Table 4. Selected Geometric Parameters for Compound 11:
Bond Distances (Å), Bond Angles (deg), and Torsion Angles
(deg)
Distances
Fe−Ct1
Fe−Ct2
Ir1−P1
Ir1-Ct3
Ir1−Cl1
Ir1−N1
1.645(2)
P1−C1
C2−C21
C21−N1
N1−S1
S1−O1
S1−O2
1.807(4)
1.491(6)
1.489(5)
1.579(3)
1.449(3)
1.439(3)
1.654(3)
2.3119(11)
1.8499(18)
2.4348(9)
2.160(3)
Angles
Ct1−Fe−Ct2
Ct3−Ir1−Cl1
Ct3−Ir1−P1
Ct3−Ir1−N1
Cl1−Ir1−P1
178.0(1)
Cl1−Ir1−N1
P1−Ir1−N1
C21−N1−S1
C21−N1−Ir1
S1−N1−Ir1
87.03(9)
85.24(9)
110.4(2)
119.0(2)
128.93(18)
116.78(5)
129.38(6)
132.04(10)
94.17(4)
Figure 4. ORTEP view of compound 11 with the atom-labeling
scheme. Displacement ellipsoids are drawn at the 30% probability
level. The H atoms have been omitted for the sake of clarity.
Other Conformational Parameters
C2−C21−N1−S1
−89.7(3)
7.6(4)
Cp(plane)−C21
Cp(plane)−N1
Cp(plane)−Ir1
−0.028(7)
−0.958(8)
−0.342(9)
τ
Cp(plane)−P1
−0.205(6)
observed at δ −0.9 can be attributed to the RL,SIr/SL,RIr
diastereoisomer. Moreover, no conversion of RL,RIr/SL,SIr to
RL,SIr/SL,RIr was observed in solution by NMR in 4 h at room
temperature, showing that the inversion of configuration at the
metal is not a facile process. This last observation underlines
the metal ability to preserve its absolute configuration, which is
an interesting point for asymmetric catalytic applications. The
observation also indirectly shows that the 1/1 diastereomeric
mixture of 11 is produced under kinetic control.
DFT Calculations. In order to test the hypothesis outlined
in Scheme 3 as the reason for the observed low-temperature
NMR behavior, we have carried out a DFT computational
study. Computational details (functional, basis sets, solvent
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model, etc.) are given in the Experimental Section. The three
compound geometries were fully optimized, without any ligand
simplification using the S planar chirality of the ferrocene ligand
and starting from the geometry observed for compound 6 in
the solid state. For the Rh and Ir complexes, analogous
geometries adapted from that of 6 were built as starting points.
Analogous starting structures were also generated for the other
H-bonded diastereoisomers and for the open form. The
energetic results are shown in Table 5, and the optimized
Hence, the computational investigation suggests that the
forming and breaking of the H bond (Scheme 3) is unlikely
to be the cause of the slow exchange phenomena observed by
low-temperature NMR for compounds 6, 8, and 10.
DFT calculations were also carried out on compound 11 in
order to verify the relative energy between the two possible
diastereoisomeric forms. The optimized geometries are shown
in the Supporting Information (part 3). The geometry of the
experimentally observed RL,RIr/SL,SIr diastereoisomer is in close
agreement with that determined by X-ray diffraction (compar-
ison available in the Supporting Information, part 4). According
to the theoretical calculations, the crystallographically charac-
terized RL,RIr/SL,SIr diastereoisomer is 11.7 kcal/mol more
stable at the Egas level than the RL,SIr/SL,RIr diastereoisomer.
Inspection of the two optimized geometries, however, does not
reveal any obvious reason for the lower stability of the RL,SIr/
SL,RIr diastereoisomer.
Table 5. Relative Energies (in kcal/mol) Computed for the
Different Isomers of Compounds 6 (Scheme 3), 8, and 10
a
isomer
ΔEgas
ΔGgas
ΔEsol
ΔGsol
6
NH···Cl1 (S)
NH···Cl2 (R)
no H bond
0.0
4.9
7.9
0.0
0.8
1.6
0.0
0.1
1.3
0.0
11.7
0.0
3.0
5.2
0.0
3.0
1.4
0.0
0.9
1.3
0.0
10.5
0.0
3.9
0.0
2.0
5.1
0.0
2.5
1.7
0.0
0.4
1.3
0.0
5.9
7.7
8
NH···Cl1 (S)
NH···Cl2 (R)
no H bond
0.0
Coordination of Ligand 5a. Since the theoretical
calculations do not support the explanation of the observed
dynamic behavior for compounds 6, 8, and 10 as a result of H
bond forming and breaking (Scheme 3) and in order to shed
further light on this phenomenon, we have synthesized a new
ligand, 5a, bearing one methyl group on the nitrogen atom
(Scheme 1). This ligand cannot establish N−H···Cl inter-
actions. Addition of 5a to a dichloromethane solution of
[Cp*RhCl2]2 afforded complex 8a in good yields (Scheme 2).
This compound has been characterized by multinuclear NMR
and mass spectrometry and by X-ray crystallography. It displays
a structure roughly similar to those of 8 and 10, with the
phosphorus atom coordinated to the metal and a dangling
amine function, resulting again in a “three-legged piano stool”
geometry. Selected geometric parameters for compound 8a are
collected in Table 3. The main difference is that the ferrocene
Cp rings in the structure of 8a form a dihedral angle midway
between the eclipsed and staggered conformations. The room-
temperature 31P{1H} NMR spectrum of 8a shows a sharp
doublet at δ 23.1 (JRh−P = 146 Hz) (Figure 3). However,
decreasing the temperature leads to broadening and decoa-
lescence in a qualitatively similar fashion at a temperature
similar to that for compound 8. Two large signals are observed
around δ 20 and 26 at 253 K. At 213 K, the higher field signal
becomes a relatively sharp doublet (JRh−P = 143 Hz), whereas
the lower field signal disappears in the noise. From this
spectrum, it seems that a third minor component may also be
present near the high-field doublet, as seen for the analogous
compound 8, although the quality of the spectrum does not
allow an unambiguous conclusion. Therefore, a fluxional
behavior also exists for compound 8a. As no hydrogen bond
is possible here, we are drawn to conclude that the structures
observed at the slow exchange limit are not related to the
establishment of H bonding at all but probably result from
different conformers related to each other by restricted rotation
around the M−P and/or the P−C(Cp) bonds. This hypothesis
seems consistent with the minor effect of the H/Me
substitution in the qualitative behavior of the NMR spectra
of compounds 8 and 8a. Of course, it is not excluded that the H
bond seen for 6, 8, and 10 in the solid state is maintained in
solution and contributes to the stabilization of the observed
conformers.
0.4
2.0
10
11
NH···Cl1 (S)
NH···Cl2 (R)
no H bond
0.0
−0.3
1.3
RL,RIr/SL,SIr
RL,SIr/SL,RIr
0.0
7.1
a
The symbol S or R in parentheses indicates the absolute configuration
at the metal center, given that the absolute configuration used in the
calculation for of the planar chiral ferrocene is S.
structures are available in the Supporting Information (part 1).
The calculated bonding parameters in the optimized structures
are in good agreement with those determined by X-ray
diffraction for the experimentally observed isomers (see
comparison in the Supporting Information, part 2). The most
stable structure corresponds to the SM form for each metal, in
agreement with the observed geometry for the crystal structure
of 6. This is true whether the comparison is made at the E or G
level in the gas phase (Egas, Ggas) or in dichloromethane
solution (Esol, Gsol), with the exception of compound 10, where
the RIr structure is slightly more stable, but only at the Esol level.
The form without a hydrogen bond has the highest energy.
Thus, the calculations suggest that the intramolecular hydrogen
bond between a chlorine atom and the pendant sulfonamide
hydrogen atom stabilizes the structure. The complex with the
highest energy difference between the open and closed forms is
6 (7.7 and 5.1 kcal/mol at the Esol and Gsol levels, respectively),
whereas this difference is on the order of 1−2 kcal/mol for
compounds 8 and 10. This indicates that compound 6 forms a
stronger H bond, in line with the X-ray structural results (Table
2). The two H-bonded isomers have very similar energies in the
solvated model, the maximum difference being observed for 6
(3.9 and 2.0 kcal/mol at the Esol and Gsol levels, respectively).
This difference appears large enough to provide only one
observable isomer for 6 in the NMR spectra at 183 K, whereas
the smaller energy differences for the isomers of compounds 8
and 10 would seem consistent with the observation of three
resonances at low temperature for these compounds. On the
other hand, the small energy difference associated with breaking
and forming the H bond should in principle ensure a very rapid
equilibration on the NMR time scale for all compounds, leading
to the expectation of only one average resonance at all
temperatures (an exchange rate of 2.47 × 103 s−1 is calculated
for the Eyring equation for a barrier of 7.7 kcal/mol at 183 K).
Hydrogenation Catalysis. As half-sandwich complexes of
ruthenium, rhodium, or iridium bearing P,N ligands have
shown efficiency in transfer hydrogenation and asymmetric
transfer hydrogenation, we were prompted to investigate the
G
dx.doi.org/10.1021/om300738q | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
activity of our compounds. Enantiomerically pure complexes 6,
8, and 10 were synthesized as described above (Scheme 2) by
coordination of the enantiomerically pure ligand 5 (R), which
was accessed according to Scheme 1 from the optically pure
alcohol 3. Acetophenone was the chosen model for our
hydrogenation studies, the catalysis being carried out under
standard conditions (Scheme 4). In basic media, one could
(10) complexes bearing a monocoordinated neutral P,N ligand
have been synthesized and fully characterized. The variable-
temperature NMR studies show dynamic behavior that, because
of the very similar behavior of 8 and 8a, cannot be attributed to
the establishment of H bonds (N−H···Cl) that are visible in the
solid state. The DFT study, while confirming the possible
existence of isomeric complexes that differ by the presence and
location of the H bond, indicates that these isomers should
interconvert too rapidly to be individually detected on the
NMR time scale. By default, the phenomenon is attributed to
restricted rotations around sterically crowded bonds. Deproto-
nation of complexes 6, 8, and 10 at the sulfonamide function
gives rise to the new complexes 7, 9, and 11, where the P-
amido ligand is bonded to the metal as a bidentate anionic
ligand.
Complexes 6, 8, and 10 show moderate catalytic activity for
the hydrogenation or transfer hydrogenation of acetophenone
by H2 or iPrOH at 50 °C. At higher temperature, complex 6
shows good catalytic activity in transfer hydrogenation. In both
cases, the enationselectivity is poor. Although poor in terms of
catalytic performance, these compounds may prove useful for
mechanistic studies that are currently in progress. Coordination
chemistry studies of these ligands on other catalytic platforms
are also planned for the near future.
Scheme 4. Catalytic Hydrogenation of Acetophenone
expect the deprotonation of the acidic proton on the
sulfonamide inducing the conversion of 6, 8, and 10 to 7, 9,
and 11, respectively. Following initial exploratory experiments,
carried out with complex 6 at 50 °C under ATH conditions (no
H2 pressure), which reached only 10% conversion after 4 days,
subsequent experiments were carried out either in the presence
of hydrogen or at a higher temperature (82 °C) (the results are
collected in Table 6). Under 30 bar of H2, significant
a
Table 6. Catalytic Hydrogenation of Acetophenone
PH
(bar)
T
t
conversion
(%)
ee
2
EXPERIMENTAL SECTION
■
entry catalyst
(°C)
base
(h)
(%)
General Considerations. All reactions were carried out using
conventional Schlenk techniques under an inert atmosphere of argon.
Thin-layer chromatography and flash chromatography were carried out
on Merck Kieselgel 60F254 precoated aluminum plates and Merck
Kieselgel 60, respectively. Solvents were dried by conventional
methods before use. Tetrafluoroboric acid diethyl ether complex
(Sigma-Aldrich), p-toluenesulfonamide (Sigma-Aldrich), and tris-
(dimethylamino)phosphine (Alfa Aesar) were used as received
without further purification. 2-thiodiphenylphosphino-
(hydroxymethyl)ferrocene (1) was synthesized according to published
procedures.29,45 GC analyses were realized with an Agilent 5890
chromatograph equipped with an FID detector and BETA DEX 225
chiral capillary column (30 m/0.25 mm/0.25 μm). NMR analyses
were performed on Bruker AV500 instruments. The spectra were
1
2
3
4
5
6
30
30
30
50
50
50
82
82
NaOH
NaOH
NaOH
KOH
6
6
6
5
5
72
32
18
99
97
1
21
29
5
8
10
6
6
NaOH
6
a
All reactions were carried out with 0.5 mmol of acetophenone, 1%
catalyst, 1.5 mL of iPrOH, and 0.025 mmol of base.
conversion took place after 6 h even at 50 °C. The best
conversion was observed with the ruthenium complex 6,
although without any significant ee. Complexes 8 and 10, on
the other hand, gave lower conversions and better, albeit still
rather low, ee values. The experiments carried out at 82 °C
under transfer hydrogenation conditions gave almost full
conversions after 5 h with either KOH or NaOH when using
complex 6, once again without notable enantioselectivity. A
kinetic study yielded a first-order decay for the substrate (k =
0.650 min−1) with 96% conversion after 5 h (Figure 5).
1
referenced internally using the signal from the residual solvent for H
and 13C and externally using 85% H3PO4 for 31P. Chemical shifts and
coupling constants are given in ppm and hertz, respectively. The
following abbreviations are used: s, singlet; d, doublet; t, triplet; quint,
quintuplet; m, multiplet; br, broad. Mass spectral analyses (GCT 1er
Waters for DCI, CH4; UPLC Xevo G2 Q TOF (Waters) for ES+)
were performed by ‘‘Service commun de spectromet
́
rie de masse’’ of
the Universite Paul-Sabatier, Toulouse, France.
́
CONCLUSIONS
Synthesis and Characterization of Compound 4. In a Schlenk
tube, 3 (250 mg, 0.58 mmol) was dissolved in 5 mL of dry
dichloromethane. A solution of tetrafluoroboric acid in ether (250 μL,
1.84 mmol) was then added. After 1 min of stirring, a solution of 1.98
g of p-toluenesulfonamide (12 mmol) in 14 mL of dry dichloro-
methane was added. After 1 min of stirring, the crude product was
separated by chromatography on silica gel with pentane/ether (7/3 v/
v) as eluent. After evaporation of the solvent, 260 mg of 4 was
obtained (yellow solid, yield 98%). 1H{31P} NMR (500 MHz, CDCl3;
δ (ppm)): 7.81 (2H, m, PPh2), 7.65 (2H, m, SO2PhCH3), 7.58 (1H,
m, PPh2), 7.54 (2H, m, PPh2), 7.52 (2H, m, PPh2), 7.47 (1H, m,
PPh2), 7.39 (2H, m, PPh2), 7.27 (2H, m, SO2PhCH3), 5.23 (1H, t, J =
6.7 Hz, subst Cp), 4.61 (1H, br, subst Cp), 4.33 (1H, s, NH), 4.30
(5H, s, Cp), 3.89 (1H, dd, J = 14.1 Hz, 6.7 Hz, CH2NH), 3.86 (1H,
dd, J = 14.1 Hz, 6.7 Hz, CH2NH), 3.77 (1H, br, subst Cp), 2.44 (3H,
s, SO2PhCH3). 13C{1H} NMR (500 MHz, CDCl3; δ (ppm)): 142.97
(quat, SO2PhCH3), 137.18 (quat, SO2PhCH3), 135.05 (JCP = 84.8 Hz,
quat, PPh2), 132.74 (JCP = 84.8 Hz, quat, PPh2), 131.97 (JCP = 10.6
Hz, PPh2), 131.72 (JCP = 10.2 Hz, PPh2), 131.57 (JCP = 3.6 Hz, PPh2),
■
We have reported herein the synthesis and coordination study
of the new chiral ferrocenyl aminophosphines 5 and 5a. A series
of half-sandwich ruthenium (6), rhodium (8, 8a), and iridium
Figure 5. Kinetics investigation of the reaction of acetophenone (0.5
mmol) in 5 mL of iPrOH with 1% of catalyst 6 (0.005 mmol) and 5%
of NaOH (0.025 mmol) at 82 °C: (left) time dependence of
conversion; (right) first-order plot.
H
dx.doi.org/10.1021/om300738q | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
131.39 (JCP = 3.6 Hz, PPh2), 129.52 (SO2PhCH3), 128.53 (JCP = 11.9
Hz, PPh2), 128.16 (JCP = 11.9 Hz, PPh2), 127.08 (SO2PhCH3), 88.71
(JCP = 11.8 Hz, quat, subst Cp), 74.88 (JCP = 12.9 Hz, subst Cp), 74.67
(JCP = 12.9 Hz, subst Cp), 73.94 (JCP = 83.9 Hz, quat, subst Cp), 70.75
(Cp), 69.28 (JCP = 10.4 Hz, subst Cp), 41.08 (CH2NH), 21.53
(SO2PhCH3). 31P{1H} NMR (500 MHz, CDCl3; δ (ppm)): 41.10.
HR/MS (DCI, CH4; m/e): 585.0649 (M, 19%) (calcd M 585.0648).
Synthesis and Characterization of Compound 5. In a Schlenk
tube, 260 mg of 4 (0.46 mmol) was dissolved in 9.16 mL of dry
toluene together with 0.5 mL of tris(dimethylamino)phosphine (2.75
mmol). The solution was kept at reflux overnight under argon. After it
was cooled to room temperature, the solution was evaporated under
reduced pressure. The crude residue was purified under argon by flash
chromatography on silica gel with dichloromethane as eluent. After
evaporation of the solvent, 236.76 mg of 5 was obtained (yellow solid,
PPh2), 7.40 (1H, t, J = 4.9 Hz, PPh2), 7.30 (2H, d, J = 7.9 Hz,
SO2PhCH3), 7.24 (1H, t, J = 5.9 Hz, PPh2), 7.23 (2H, m, PPh2), 7.18
(2H, m, PPh2), 4.65 (1H, dd, J = 2.5, 1.2 Hz, subst Cp), 4.37 (1H, t, J
= 2.5 Hz, subst Cp), 4.03 (5H, s, Cp), 4.4 (1H, d, J = 14.1 Hz CH2N),
4.12 (1H, d, J = 14.1 Hz, CH2N), 3.90 (1H, dd, J = 2.5, 1.2 Hz, subst
Cp), 2.45 (3H, s, SO2PhCH3). 2.32 (3H, s, NCH3). 13C{1H} NMR
(500 MHz, CDCl3; δ (ppm)): 143.10 (quat, SO2PhCH3), 139.52 (JCP
= 8.9 Hz, quat, PPh2), 137.31 (JCP = 8.9 Hz, quat, PPh2), 135.03 (JCP
=
21.5 Hz, PPh2), 134.84 (quat, SO2PhCH3), 132.48 (JCP = 18.6 Hz,
PPh2), 129.61 (SO2Ar), 129.22 (PPh2), 128.16 (JCP = 8.2 Hz, PPh2),
128.06 (JCP = 6.0 Hz, PPh2), 128.00 (PPh2), 127.49 (SO2Ar), 88.18
(JCP = 25.7 Hz, quat, subst Cp), 76.28 (JCP = 9.7 Hz, quat, subst Cp),
73.07 (JCP = 4.2 Hz, subst Cp), 71.81 (JCP = 4.2 Hz, subst Cp), 70.22
(subst Cp), 69.91 (Cp), 48.50 (JCP = 10.4 Hz, CH2N), 34.34 (NCH3),
21.54 (SO2PhCH3). 31P{1H} NMR (500 MHz, CDCl3; δ (ppm)):
−25.37. HR/MS (ES+; m/e): 568.1169 (M, 100%) (calcd M
568.1162).
Synthesis and Characterization of Compound 6. In a Schlenk
tube under argon, a mixture of compound 5 (10 mg, 0.018 mmol) and
[Ru(p-cymene)Cl2]2 (5.53 mg, 0.009 mmol) was dissolved in dry
dichloromethane (2 mL). The reaction was carried at room
temperature for 1 h. The solvent was evaporated, and the resulting
red solid was washed with dry pentane. After evaporation of the
solvent, 15.32 mg of 6 was obtained (yield 99%). 1H{31P} NMR (500
MHz, CDCl3; δ (ppm)): 8.41 (2H, m, PPh2), 7.92 (2H, m, PPh2),
7.61 (2H, m, SO2PhCH3), 7.47 (3H, m, PPh2), 7.29 (1H, m, PPh2),
7.28 (2H, m, SO2PhCH3), 7.15 (2H, m, PPh2), 5.78 (1H, br, NH),
5.28 (2H, m, Ph/Cym), 4.98 (1H, m, Ph/Cym), 4.86 (1H, m, Ph/
Cym), 4.85 (1H, s, subst Cp), 4.55 (1H, s, subst Cp), 4.50 (1H, s,
subst Cp), 4.10 (5H, s, Cp), 3.41 (1H, dd, J = 13.4 Hz, 8.4 Hz,
CH2NH), 2.72 (1H, dd, J = 13.7 Hz, 3.5 Hz, CH2NH), 2.66 (1H,
heptuplet, J = 6.9 Hz, CH(CH3)2), 2.47 (3H, s, SO2PhCH3), 1.68
(3H, s, PhCH3/Cym), 1.03 (3H, d, J = 6.9 Hz, CH(CH3)2), 0.91 (3H,
d, J = 6.9 Hz, CH(CH3)2). 13C{1H} NMR (500 MHz, CDCl3; δ
(ppm)): 142.70 (quat, SO2PhCH3), 137.64 (quat, SO2PhCH3), 136.80
1
yield 93%). H{31P} NMR (500 MHz, CDCl3; δ (ppm)): 7.55 (2H,
m, SO2PhCH3), 7.47 (2H, m, PPh2), 7.40 (2H, m, PPh2), 7.39 (1H, m,
PPh2), 7.31 (2H, m, PPh2), 7.31 (1H, m, PPh2), 7.25 (2H, m,
SO2PhCH3), 7.11 (2H, m, PPh2), 4.43 (1H, dd, J = 4.3 Hz, 2.4 Hz,
subst Cp), 4.27 (1H, t, J = 2.5 Hz, subst Cp), 4.22 (1H, t, J = 6.1 Hz,
NH), 4.07 (5H, s, Cp), 4.00 (1H, dd, J = 13.2 Hz, 6.5 Hz, CH2NH),
3.98 (1H, dd, J = 13.3 Hz, 5.1 Hz, CH2NH), 3.71 (1H, dd, J = 2.3 Hz,
1.1 Hz, subst Cp), 2.44 (3H, s, SO2PhCH3). 13C{1H} NMR (500
MHz, CDCl3; δ (ppm)): 143.17 (quat, SO2PhCH3), 139.14 (JCP
=
10.4 Hz, quat, PPh2), 136.77 (quat, SO2PhCH3), 136.31 (JCP = 8 Hz,
quat, PPh2), 134.61 (JCP = 20.6 Hz, PPh2), 132.48 (JCP = 18.8 Hz,
PPh2), 129.59 (SO2PhCH3), 129.30 (PPh2), 128.62 (PPh2), 128.57
(JCP = 6.3 Hz, PPh2), 128.29 (JCP = 8 Hz, PPh2), 127.03 (SO2PhCH3),
87.93 (JCP = 24.2 Hz, quat, subst Cp), 76.29 (JCP = 7.0 Hz, quat, subst
Cp), 72.07 (JCP = 2.9 Hz, subst Cp), 71.62 (JCP = 2.9 Hz, subst Cp),
69.73 (Cp), 69.70 (subst Cp), 41.82 (CH2NH), 21.55 (SO2PhCH3).
31P{1H} NMR (500 MHz, CDCl3; δ (ppm)): −24.24. HR/MS (DCI,
CH4; m/e): 554.1006 (M + 1, 100%) (calcd M + 1 554.0927).
Synthesis and Characterization of Compound 4a. In a
Schlenk tube, 200 mg of 3 (0.46 mmol) was dissolved in 4 mL of
dry dichloromethane. A solution of tetrafluoroboric acid in ether (200
μL, 1.47 mmol) was then added. After 1 min of stirring, a solution of
1.7 g of N-methyl-p-toluenesulfonamide (9.26 mmol) in 10 mL of dry
dichloromethane was added. After 1 min of stirring, the crude product
was separated by chromatography on silica gel with pentane/ether (7/
3 v/v) as eluent. After evaporation of the solvent, 275.8 mg of 4a was
obtained (yellow solid, yield 100%). 1H{31P} NMR (500 MHz,
CDCl3; δ (ppm)): 7.84 (2H, m, PPh2), 7.62 (2H, m, PPh2), 7.61 (2H,
m, SO2PhCH3), 7.55 (1H, m, PPh2), 7.50 (1H, m, PPh2), 7.45 (2H, m,
PPh2), 7.37 (2H, m, PPh2), 7.30 (2H, m, SO2PhCH3), 4.95 (1H, m,
subst Cp), 4.37 (1H, t, J = 2.4 Hz, subst Cp), 4.69 (1H, d, J = 15.5 Hz
CH2N), 4.35 (5H, s, Cp), 4.29 (1H, d, J = 15.5 Hz, CH2N), 3.78 (1H,
br, subst Cp), 2.44 (3H, s, SO2PhCH3). 2.38 (3H, s, NCH3). 13C{1H}
NMR (500 MHz, CDCl3; δ (ppm)): 143.16 (quat, SO2PhCH3),
134.63 (JCP = 85.6 Hz, quat, PPh2), 133.14 (JCP = 85.6 Hz, quat,
PPh2), 132.05 (JCP = 10.4 Hz, PPh2), 134.86 (quat, SO2PhCH3),
131.99 (JCP = 10.4 Hz, PPh2), 129.65 (SO2PhCH3), 131.41 (JCP = 3.0
Hz, PPh2), 131.33 (JCP = 3.0 Hz, PPh2), 128.32 (JCP = 11.9 Hz, PPh2),
128.08 (JCP = 11.9 Hz, PPh2), 127.38 (SO2PhCH3), 88.58 (JCP = 11.5
Hz, quat, subst Cp), 73.77 (JCP = 92.2 Hz, quat, subst Cp), 74.79 (JCP
= 8.9 Hz, subst Cp), 74.49 (JCP = 12.1 Hz, subst Cp), 69.58 (JCP = 10.4
Hz, subst Cp), 71.07 (Cp), 48.71 (CH2N), 35.55 (NCH3), 21.50
(SO2PhCH3). 31P{1H} NMR (500 MHz, CDCl3; δ (ppm)): 41.07.
HR/MS (ES+; m/e): 599.0820 (M, 30%) (calcd M 599.0805);
622.0718 (M + Na, 100%) (calcd M + Na 622.0703).
(JCP = 45 Hz, quat, PPh2), 135.15 (JCP = 9.5 Hz, PPh2), 133.58 (JCP
=
9.5 Hz, PPh2), 131.91 (JCP = 45 Hz, quat, PPh2), 130.49 (JCP = 2.1 Hz
PPh2), 130.43 (PPh2), 129.50 (SO2PhCH3), 127.89 (JCP = 10.3 Hz,
PPh2), 127.40 (JCP = 10.3 Hz, PPh2), 127.06 (SO2PhCH3), 110.74
(quat, Ph/Cym), 94.23 (quat, Ph/Cym), 92.73 (Ph/Cym), 89.10 (Ph/
Cym), 87.49 (JCP = 7.6 Hz, Ph/Cym), 86.50 (JCP = 7.6 Hz, quat, subst
Cp), 83.82 (Ph/Cym), 78.39 (JCP = 38.2 Hz, quat, subst Cp), 76.10
(JCP = 14.3 Hz, subst Cp), 73.31 (JCP = 7.2 Hz, subst Cp), 71.03 (Cp),
70.22 (JCP = 8.3 Hz, subst Cp), 40.85 (CH2NH), 30.10 (CH/Cym),
22.23 (CHCH3/Cym), 21.55(SO2PhCH3), 21.17 (CHCH3/Cym),
17.18 (PhCH3/Cym). 31P{1H} NMR (500 MHz, CDCl3; δ (ppm)):
14.60. HR/MS (ES+; m/e): 824.0756 (M − Cl, 70%) (calcd M − Cl
824.0755).
Synthesis and Characterization of Compound 7. In a Schlenk
tube under argon, compound 6 (15.47 mg, 0.018 mmol) was dissolved
in dry dichloromethane (2 mL) and then triethylamine (12.54 μL, 0.09
mmol) was added. The reaction was carried at 40 °C for 1.5 h. The
solvent was evaporated, and the resulting red solid was washed with
dry pentane. After evaporation of the solvent, 11.87 mg of 7 was
obtained (yield 80%). Data for the first diastereoisomer are as follows.
1H{31P} NMR (500 MHz, CDCl3; δ (ppm)): 8.50−7.20 (10H, m,
PPh2), 7.81 (2H, m, SO2PhCH3), 7.31 (2H, m, SO2PhCH3), 5.79 (1H,
m, Ph/Cym), 5.21 (1H, d, J = 15.3 Hz, CH2N), 5.15 (1H, m, Ph/
Cym), 4.89 (1H, m, Ph/Cym), 4.74 (1H, m, Ph/Cym), 4.39 (1H, br,
subst Cp), 4.10 (1H, br, subst Cp), 4.09 (1H, d, J = 17.8 Hz, CH2N),
3.99 (1H, br, subst Cp), 3.67 (5H, s, Cp), 2.95 (1H, heptuplet, J = 7.2
Hz, CH(CH3)2), 2.45 (3H, s, SO2PhCH3), 1.27 (3H, d, J = 6.2 Hz,
CH(CH3)2), 1.24 (3H, d, J = 6.2 Hz, CH(CH3)2), 0.56 (3H, s,
PhCH3/Cym). 13C{1H} NMR (500 MHz, CDCl3; δ (ppm)): 143.09
(quat, SO2PhCH3), 140.59 (quat, SO2PhCH3), 138.80 (JCP = 49.1 Hz,
quat, PPh2), 132.52 (JCP = 8 Hz, PPh2), 131.07 (PPh2), 129.60 (PPh2),
129.49 (JCP = 13.2 Hz, PPh2), 129.49 (SO2PhCH3), 128.07 (JCP = 10.4
Hz, PPh2), 127.3 (JCP = 8.9 Hz, PPh2), 126.55 (SO2PhCH3), 124.88
(quat, Ph/Cym), 98.94 (JCP = 13.6 Hz, quat, subst Cp), 98.53 (Ph/
Cym), 92.78 (quat, Ph/Cym), 85.45 (Ph/Cym), 83.18 (Ph/Cym),
Synthesis and Characterization of Compound 5a. In a
Schlenk tube, 300 mg of 4a (0.50 mmol) was dissolved in 9.8 mL
of dry toluene together with 0.46 mL of tris(dimethylamino)-
phosphine (2.51 mmol). The solution was kept at reflux overnight
under argon. After it was cooled to room temperature, the solution
was evaporated in vacuo. The crude residue was purified under argon
by flash chromatography on silica gel with dichloromethane as eluent.
After evaporation of the solvent, 283.8 mg of 5a was obtained (yellow
1
solid, yield 100%). H{31P} NMR (500 MHz, CDCl3; δ (ppm)): 7.64
(2H, d, J = 8.0 Hz, SO2PhCH3), 7.58 (2H, m, PPh2), 7.41 (2H, m,
I
dx.doi.org/10.1021/om300738q | Organometallics XXXX, XXX, XXX−XXX

Organometallics
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75.11 (Ph/Cym), 70.54(Cp), 70.1 (JCP = 49.2 Hz, subst Cp), 69.09
(JCP = 7.7 Hz, subst Cp), 68.13 (subst Cp), 44.81 (CH2N), 31.13
(CH/Cym), 23.70 (CHCH3/Cym), 21.68 (SO2PhCH3), 12.61
(PhCH3/Cym). 31P{1H} NMR (500 MHz, CDCl3; δ (ppm)): 18.31.
Hz, quat, subst Cp), 79.99 (quat, subst Cp), 71.82 (JCP = 5.3 Hz, subst
Cp), 70.52 (subst Cp), 71.43 (Cp), 68.35 (JCP = 9.1 Hz, subst Cp),
50.22 (CH2NH), 35.72 (NCH3), 21.50 (SO2PhCH3), 8.59 (CH3/
Cp*). 31P{1H} NMR (500 MHz, CDCl3; δ (ppm)): 23.10 (d, J =
145.83 Hz). HR/MS(DCI, CH4; m/e): 840.1002 (M − Cl, 100%)
(calcd M − Cl 840.1002).
1
Data for the second diastereoisomer are as follows. H{31P} NMR
(500 MHz, CDCl3; δ (ppm)): 8.50−7.20 (10H, m, PPh2), 7.89 (2H,
m, SO2PhCH3), 7.31 (2H, m, SO2PhCH3), 5.57 (1H, m, Ph/Cym),
5.24 (1H, m, Ph/Cym), 4.59 (1H, m, Ph/Cym), 4.44 (1H, d, J = 23
Hz, CH2N), 4.36 (1H, d, J = 38.8 Hz, CH2N), 4.22 (1H, m, Ph/Cym),
4.16 (1H, t, J = 2.5 Hz, subst Cp), 4.10 (1H, br, subst Cp), 4.04 (1H,
br, subst Cp), 3.53 (5H, s, Cp), 2.63 (1H, heptuplet, J = 7.4 Hz,
CH(CH3)2), 2.45 (3H, s, SO2PhCH3), 1.91 (3H, s, PhCH3/Cym),
0.98 (3H, d, J = 6.8 Hz, CH(CH3)2), 0.94 (3H, d, J = 6.8 Hz,
CH(CH3)2). 13C{1H} NMR (500 MHz, CDCl3; δ (ppm)): 143.32
(quat, SO2PhCH3), 140.65 (quat, SO2PhCH3), 136.16 (JCP = 47.0 Hz,
quat, PPh2), 134.80 (JCP = 47.0 Hz, quat, PPh2), 131.46 (JCP = 9.9 Hz,
PPh2), 131.15 (PPh2), 129.91 (PPh2), 129.44 (JCP = 12.7 Hz, PPh2),
128.19 (SO2PhCH3), 128.15 (JCP = 9.8 Hz, PPh2), 127.33 (JCP = 9.5
Hz, PPh2), 126.48 (SO2PhCH3), 118.34 (quat, Ph/Cym), 89.85 (Ph/
Cym), 96.97 (quat, Ph/Cym), 84.90 (Ph/Cym), 84.31 (Ph/Cym),
87.53 (Ph/Cym), 95.99 (JCP = 12.4 Hz, quat, subst Cp), 70.06 (subst
Cp), 70.42(Cp), 66.56 (JCP = 6.6 Hz, subst Cp), 67.91 (JCP = 4.5 Hz,
subst Cp), 47.67 (CH2N), 30.24 (CH/Cym), 22.98 (CHCH3/Cym),
21.68 (SO2PhCH3), 20.46 (CHCH3/Cym), 19.55 (PhCH3/Cym).
31P{1H} NMR (500 MHz, CDCl3; δ (ppm)): 26.56. HR/MS (ES+; m/
e): 824.0768 (M + H+, 30%) (calcd M + H+ 824.0755).
Synthesis and Characterization of Compound 9. In a Schlenk
tube under argon, compound 8 (15.56 mg, 0.018 mmol) was dissolved
in dry dichloromethane (2 mL), and then triethylamine (12.54 μL,
0.09 mmol) was added. The reaction was carried out at room
temperature for one night. The solvent was evaporated, and the
resulting red solid was washed with dry pentane. After evaporation of
the solvent, 11.29 mg of 9 was obtained (yield 76%). Data for the first
1
diastereoisomer are as follows. H{31P} NMR (500 MHz, CDCl3; δ
(ppm)): 8.41 (2H, m, PPh2), 7.86 (2H, m, SO2PhCH3), 7.80 (2H, m,
PPh2), 7.71 (2H, m, PPh2), 7.65 (1H, m, PPh2), 7.41 (1H, m, PPh2),
7.34 (2H, m, PPh2), 7.25 (2H, m, SO2PhCH3), 4.44 (1H, d, J = 16.0
Hz, CH2N), 4.14 (1H, dd, J = 2.3, 1.1 Hz, subst Cp), 4.09 (1H, t, J =
2.4 Hz, subst Cp), 3.95 (1H, d, J = 15.7 Hz, CH2N), 3.93 (1H, dd, J =
1.9, 1.0 Hz, subst Cp), 3.56 (5H, s, Cp), 2.40 (3H, s, SO2PhCH3), 1.21
(15H, s, Cp*). 13C{1H} NMR (500 MHz, CDCl3; δ (ppm)): 144.26
(quat, SO2PhCH3), 140.00 (quat, SO2PhCH3), 136.30 (JCP = 11.7 Hz,
PPh2), 134.0 (JCP = 7 Hz, PPh2), 133.19 (JCP = 47.0 Hz, quat, PPh2),
132.96 (JCP = 50.0 Hz, quat, PPh2), 131.41 (PPh2), 130.21 (PPh2),
129.05 (SO2PhCH3), 128.29 (JCP = 11.4 Hz, PPh2), 126.85 (JCP = 9.8
Hz, PPh2), 126.75 (SO2PhCH3), 100.50 (JCP = 3.2 Hz, quat, CCH3/
Cp*), 95.71 (JCP = 13.3 Hz, quat, subst Cp), 75.54 (JCP = 53.8 Hz,
quat, subst Cp), 70.55 (subst Cp), 70.33(Cp), 67.90 (JCP = 8.0 Hz,
subst Cp), 65.89 (JCP = 8.0 Hz, subst Cp), 47.09 (CH2N), 21.38
(SO2PhCH3), 9.38 (CCH3/Cp*). 31P{1H} NMR (500 MHz, CDCl3;
δ (ppm)): 30.93 (d, J = 142.8 Hz). 103Rh{31P} NMR (500 MHz,
CDCl3; δ (ppm)): −6263. Data for the second diastereoisomer are as
Synthesis and Characterization of Compound 8. In a Schlenk
tube under argon, a mixture of compound 5 (10 mg, 0.018 mmol) and
[RhCp*Cl2]2 (5.56 mg, 0.009 mmol) was dissolved in dry dichloro-
methane (2 mL). The reaction was carried out at room temperature
for 1 h. The solvent was evaporated, and the resulting red solid was
washed with dry pentane. After evaporation of the solvent, 15.35 mg of
1
follows. H{31P} NMR (500 MHz, CDCl3; δ (ppm)): 8.32 (2H, m,
1
8 was obtained (yield 99%). H{31P} NMR (500 MHz, CDCl3; δ
PPh2), 7.75 (2H, m, SO2PhCH3), 7.65 (2H, m, PPh2), 7.65 (2H, m,
PPh2), 7.64 (1H, m, PPh2), 7.38 (2H, m, PPh2), 7.34 (1H, m, PPh2),
7.23 (2H, m, SO2PhCH3), 5.19 (1H, d, J = 15.4 Hz, CH2N), 4.30 (1H,
dd, J = 2.1 Hz, 1.1 Hz, subst Cp), 4.06 (1H, t, J = 2.5 Hz, subst Cp),
3.91 (1H, dd, J = 2.3, 1.0 Hz, subst Cp), 3.73 (5H, s, Cp), 3.63 (1H, d,
J = 15.7 Hz, CH2N), 2.40 (3H, s, SO2PhCH3), 1.26 (15H, s, Cp*).
13C{1H} NMR (500 MHz, CDCl3; δ (ppm)): 144.92 (quat,
SO2PhCH3), 140.00 (quat, SO2PhCH3), 135.89 (JCP = 10.7 Hz,
PPh2), 135.79 (JCP = 48.1 Hz, quat, PPh2), 132.80 (JCP = 50.7 Hz, quat,
PPh2), 132.71 (JCP = 8.9 Hz, PPh2), 131.47 (PPh2), 129.79 (PPh2),
129.04 (SO2Ar), 128.23 (JCP = 10.0 Hz, PPh2), 127.67 (JCP = 9.8 Hz,
PPh2), 126.34 (SO2PhCH3), 100.55 (JCP = 2.5 Hz, quat, CCH3/Cp*),
98.64 (JCP = 13.2 Hz, quat, subst Cp), 71.78 (JCP = 49.3 Hz, quat,
subst Cp), 70.43(Cp), 69.63 (subst Cp), 69.00 (JCP = 7.9 Hz, subst
Cp), 68.05 (JCP = 6.5 Hz, subst Cp), 45.49 (CH2N), 21.38
(SO2PhCH3), 9.18 (CCH3/Cp*) 31P{1H} NMR (500 MHz, CDCl3;
δ (ppm)): 19.61 (d, J = 147.0 Hz). 103Rh{31P} NMR (500 MHz,
CDCl3; δ (ppm)): −6179. HR/MS (DCI, CH4; m/e): 790.1078 (M −
Cl, 50%) (calcd M − Cl 790.1078).
(ppm)): 8.32 (2H, m, PPh2), 7.95 (2H, m, PPh2), 7.60 (2H, m,
SO2PhCH3), 7.54 (1H, m, PPh2), 7.48 (2H, m, PPh2), 7.47 (1H, m,
PPh2), 7.35 (2H, m, PPh2), 7.34 (2H, m, SO2PhCH3), 5.69 (1H, br,
NH), 4.96 (1H, s, subst Cp), 4.47 (1H, s, subst Cp), 4.28 (1H, s, subst
Cp), 3.97 (5H, s, Cp), 3.37 (1H, dd, J = 13.8 Hz, 8.3 Hz, CH2NH),
2.75 (1H, dd, J = 10.5 Hz, 4.1 Hz, CH2NH), 2.51 (3H, s, SO2PhCH3),
1.28 (15H, s, Cp*). 13C{1H} NMR (500 MHz, CDCl3; δ (ppm)):
143.03 (quat, SO2PhCH3), 137.77 (quat, SO2PhCH3), 135.21 (JCP
=
5.9 Hz, PPh2), 134.38 (JCP = 10 Hz, PPh2), 133.11 (JCP = 43 Hz, quat,
PPh2), 131.00 (JCP = 2.1 Hz PPh2), 130.59 (JCP = 2.1 Hz, PPh2),
129.51 (SO2PhCH3), 127.71 (JCP = 9.4 Hz, PPh2), 127.65 (JCP = 8.4
Hz, PPh2), 127.03 (SO2PhCH3), 99.13 (JCP = 2.8, quat, CCH3/Cp*),
86.31 (JCP = 5.3 Hz, quat, subst Cp), 77.68 (JCP = 17.8 Hz, subst Cp),
75.99 (JCP = 41.9 Hz, quat, subst Cp), 72.74 (JCP = 4.5 Hz, subst Cp),
70.70 (Cp), 69.68 (JCP = 9.3 Hz, subst Cp), 41.19 (CH2NH),
21.23(SO2PhCH3), 8.44 (CH3/Cp*). 31P{1H} NMR (500 MHz,
CDCl3; δ (ppm)): 24.20 (d, J = 133.67 Hz). HR/MS (DCI, CH4; m/
e): 790.1078 (M − HCl2, 100%) (calcd M − HCl2 790.1078).
Synthesis and Characterization of Compound 8a. In a
Schlenk tube under argon, a mixture of compound 5a (10 mg, 0.018
mmol) and [RhCp*Cl2]2 (5.56 mg, 0.009 mmol) was dissolved in dry
dichloromethane (2 mL). The reaction was carried out at room
temperature for 1 h. The solvent was evaporated, and the resulting red
solid was washed with dry pentane. After evaporation of the solvent,
Synthesis and Characterization of Compound 10. In a
Schlenk tube under argon, a mixture of compound 5 (10 mg, 0.018
mmol) and [IrCp*Cl2]2 (7.17 mg, 0.009 mmol) was dissolved in dry
dichloromethane (2 mL). The reaction was carried out at room
temperature for one night. The solvent was evaporated, and the
resulting yellow solid was washed with dry pentane. After evaporation
1
13.07 mg of 8a was obtained (yield 83%). H{31P} NMR (500 MHz,
1
CDCl3; δ (ppm)): 8.36 (2H, m, PPh2), 7.81 (2H, m, PPh2), 7.51 (1H,
m, PPh2), 7.48 (2H, m, PPh2), 7.44 (2H, m, SO2PhCH3), 7.43 (1H, m,
PPh2), 7.38 (2H, m, PPh2), 7.29 (2H, m, SO2PhCH3), 4.67 (1H, s,
subst Cp), 4.47 (1H, s, subst Cp), 4.22 (1H, s, subst Cp), 3.99 (5H, s,
Cp), 3.62 (1H, d, J = 15.5 Hz, CH2NH), 3.35 (1H, d, J = 15.5 Hz,
CH2NH), 2.54 (3H, s, NCH3), 2.47 (3H, s, SO2PhCH3), 1.27 (15H, s,
Cp*). 13C{1H} NMR (500 MHz, CDCl3; δ (ppm)): 143.16 (quat,
SO2PhCH3), 134.37 (quat, SO2PhCH3), 135.43 (JCP = 7.0 Hz, PPh2),
134.38 (PPh2), 133.71 (quat, PPh2), 131.56 (quat, PPh2), 130.57 (JCP
= 2.7 Hz PPh2), 130.39 (JCP = 2.7 Hz, PPh2), 129.51 (SO2PhCH3),
127.68 (JCP = 9.8 Hz, PPh2), 127.39 (JCP = 11.6 Hz, PPh2), 127.39
(SO2PhCH3), 98.85 (JCP = 3.1, quat, CCH3/Cp*), 86.40 (JCP = 3.6
of the solvent, 16.94 mg of 10 was obtained (yield 99%). H{31P}
NMR (500 MHz, CDCl3; δ (ppm)): 8.32 (2H, m, PPh2), 7.85 (2H, m,
PPh2), 7.60 (2H, m, SO2PhCH3), 7.47 (1H, m, PPh2), 7.42 (2H, m,
PPh2), 7.44 (1H, m, PPh2), 7.37 (2H, m, PPh2), 7.28 (2H, m,
SO2PhCH3), 5.10 (1H, br, NH), 5.05 (1H, s, subst Cp), 4.41 (1H, s,
subst Cp), 4.28 (1H, s, subst Cp), 3.92 (5H, s, Cp), 3.38 (1H, dd, J =
14.2, 6.2 Hz, CH2NH), 3.01 (1H, dd, J = 10.6, 4.6 Hz, CH2NH), 2.47
(3H, s, SO2PhCH3), 1.27 (15H, s, Cp*). 13C{1H} NMR (500 MHz,
CDCl3; δ (ppm)): 142.68 (quat, SO2Ar), 137.63 (quat, SO2Ar),
134.71 (JCP = 9.9 Hz, PPh2), 134.52 (JCP = 9.9 Hz, PPh2), 133.04 (JCP
= 55.2 Hz, quat, PPh2), 131.41 (JCP = 55.2 Hz, quat, PPh2), 130.84
(JCP = 2.0 Hz, PPh2), 130.57 (JCP = 2.6 Hz, PPh2), 129.46 (SO2Ar),
J
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127.68 (JCP = 9.5 Hz, PPh2), 127.50 (JCP = 10.4 Hz, PPh2), 127.15
(SO2Ar), 92.63 (JCP = 2.5 Hz, quat, CCH3/Cp*), 86.11 (JCP = 5.5 Hz,
quat, subst Cp), 78.84 (JCP = 19.7 Hz, subst Cp), 75.76 (JCP = 51.2 Hz,
quat, subst Cp), 72.64 (JCP = 6.3 Hz, subst Cp), 70.65 (Cp), 69.29 (JCP
= 9.5 Hz, subst Cp), 41.42 (CH2NH), 21.47 (SO2PhCH3), 8.1 (CH3/
Cp*) 31P{1H} NMR (500 MHz, CDCl3; δ (ppm)): −7.0. HR/MS
(ES+): 916.1400 (M − Cl, 35%) (calcd M − Cl 916.1419).
through a short silica gel column before being analyzed by GC on a
chiral column.
X-ray Structural Analyses. A single crystal of each compound
was mounted under inert perfluoropolyether at the tip of a glass fiber
and cooled in the cryostream of either an Oxford-Diffraction
XCALIBUR CCD diffractometer for 4 and 6 or an Agilent
Technologies GEMINI EOS diffractometer for 8, 8a, 10, and 11.
The structures were solved by direct methods (SIR97)36 and refined
by least-squares procedures on F2 using SHELXL-97.37 All H atoms
attached to carbon atoms were introduced in the calculation at
idealized positions and treated as riding models. In compound 8a,
owing to the poor quality of the data, some residual electron density
was difficult to model. Therefore, the SQUEEZE function of
PLATON38 was used to eliminate the contribution of the electron
density in the solvent region from the intensity data, and the solvent-
free model was employed for the final refinement. There are two large
cavities of 769 Å3 per unit cell. PLATON estimated that each cavity
contains about 138 electrons, which may correspond to a mixture of
dichloromethane and diethyl ether in the ratio 1/2. Both solvents were
used to crystallize the compound. The drawing of the molecules was
realized with the help of ORTEP3239 or PLATON.38 Crystal data and
refinement parameters are available in the Supporting Information
(part 6).
Crystallographic data (excluding structure factors) for the structures
reported in this paper have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publications CCDC-
6893066 (4), CCDC-6893067 (6), CCDC-6893068 (8), CCDC-
6893069 (8a), CCDC-6893070 (10), and CCDC-6893071 (11).
Copies of the data can be obtained free of charge on application to the
CCDC, 12 Union Road, Cambridge CB2 IEZ, U.K. (fax, int. code
+44(1223)336-033; e-mail, deposit@ccdc.cam.ac.uk).
Computational Details. All calculations were carried out at the
DFT level by means of the dispersion-corrected functional M06 as
implemented in the Gaussian09 program package.40 Ir, Fe, Rh, and Ru
atoms were described using the LANL2DZ effective core potential41,42
for the inner electrons and its associated double-ζ basis set for the
outer electrons. Additionally, f polarization shells (exponents 0.938,
2.462, 1.350, and 1.235, respectively)43 were also added for these
metal atoms. For C, O, S, P, H, Cl, and N atoms the 6-31G(d,p) and
the 6-31+G(d) basis sets were used, respectively. Geometries of all the
metal complexes were fully optimized without any symmetry
constraints. Harmonic force constants were computed at the
optimized geometries, confirming the nature of these stationary points
as minima. Solvent effects (CH2Cl2, ε = 8.930) were introduced
through single-point calculations at optimized gas-phase geometries by
means of a continuum method, the SMD solvation model44
implemented in Gaussian09. The relative Gibbs energies in dichloro-
methane (ΔGsol) were obtained by employing the scheme
Synthesis and Characterization of Compound 11. In a
Schlenk tube under argon, compound 10 (17.17 mg, 0.018 mmol)
was dissolved in dry dichloromethane (2 mL) and then triethylamine
(12.54 μL, 0.09 mmol) was added. The reaction was carried out at
room temperature for one night. The solvent was evaporated, and the
resulting yellow solid was washed with dry pentane. After evaporation
of the solvent, 12.84 mg of 11 was obtained (yield 78%). Data for the
first diastereoisomer are as follows. 1H{31P} NMR (500 MHz, CDCl3;
δ (ppm)): 8.24 (2H, m, PPh2), 7.68 (2H, m, SO2PhCH3), 7.64 (2H,
m, PPh2), 7.64 (1H, m, PPh2), 7.58 (2H, m, PPh2), 7.36 (2H, m,
PPh2), 7.29 (1H, m, PPh2), 7.23 (2H, m, SO2PhCH3), 5.64 (1H, d, J =
15.4 Hz, CH2N), 4.33 (1H, br, subst Cp), 4.04 (1H, t, J = 2.3 Hz,
subst Cp), 3.89 (1H, br, subst Cp), 3.78 (1H, d, J = 15.4 Hz, CH2N),
3.73 (5H, s, Cp), 2.40 (3H, s, SO2PhCH3), 1.26 (15H, s, Cp*).
13C{1H} NMR (500 MHz, CDCl3; δ (ppm)): 143.90 (quat,
SO2PhCH3), 140.28 (quat, SO2PhCH3), 136.33 (JCP = 56.4 Hz,
quat, PPh2), 135.83 (JCP = 11.7 Hz, PPh2), 132.53 (JCP = 8.8 Hz,
PPh2), 131.41 (PPh2), 129.61 (PPh2), 129.25 (JCP = 57.3 Hz, quat,
PPh2), 129.14 (SO2PhCH3), 128.00 (JCP = 10.7 Hz, PPh2), 127.41 (JCP
= 10.7 Hz, PPh2), 126.28 (SO2PhCH3), 97.98 (JCP = 11.6 Hz, quat,
subst Cp), 94.32 (JCP = 2.8 Hz, quat, CCH3/Cp*), 71.35 (JCP = 57.6
Hz, quat, subst Cp), 70.34 (Cp), 69.91 (subst Cp), 69.19 (JCP = 7.9
Hz, subst Cp), 67.81 (JCP = 6.6 Hz, subst Cp), 45.16 (CH2N), 21.38
(SO2PhCH3), 8.68 (CCH3/Cp*). 31P{1H} NMR (500 MHz, CDCl3;
δ (ppm)): −10.13 (s). Data for the second diastereoisomer are as
1
follows. H{31P} NMR (500 MHz, CDCl3; δ (ppm)): 8.37 (2H, m,
PPh2), 7.78 (2H, m, SO2PhCH3), 7.73 (2H, m, PPh2), 7.69 (2H, m,
PPh2), 7.61 (1H, m, PPh2), 7.36 (1H, m, PPh2), 7.33 (2H, m, PPh2),
7.23 (2H, m, SO2PhCH3), 4.61 (1H, d, J = 15.2 Hz, CH2N), 4.17 (1H,
br, subst Cp), 4.09 (1H, t, J = 2.2 Hz, subst Cp), 3.92 (1H, br, subst
Cp), 3.88 (1H, d, J = 15.0 Hz, CH2N), 3.58 (5H, s, Cp), 2.40 (3H, s,
SO2PhCH3), 1.21 (15H, s, Cp*). 13C{1H} NMR (500 MHz, CDCl3; δ
(ppm)): 143.90 (quat, SO2PhCH3), 140.36 (quat, SO2PhCH3), 136.40
(JCP = 13.0 Hz, PPh2), 133.98 (JCP = 8.0 Hz, PPh2), 133.12 (JCP = 57.5
Hz, quat, PPh2), 132.51 (JCP = 59.6 Hz, quat, PPh2), 131.41 (PPh2),
130.10 (PPh2), 129.14 (SO2PhCH3), 128.13 (JCP = 11.3 Hz, PPh2),
126.72 (JCP = 9.6 Hz, PPh2), 126.55 (SO2PhCH3), 95.07 (JCP = 12.5
Hz, quat, subst Cp), 93.98 (JCP = 2.8 Hz, quat, CCH3/Cp*), 75.52
(JCP = 60 Hz, quat, subst Cp), 70.77 (subst Cp), 70.39(Cp), 67.62 (JCP
= 7.6 Hz, subst Cp), 65.88 (JCP = 8.2 Hz, subst Cp), 46.98 (CH2N),
21.38 (SO2PhCH3), 8.92 (CCH3/Cp*). 31P{1H} NMR (500 MHz,
CDCl3; δ (ppm)): −0.89 (s). HR/MS (DCI, CH4): 880.1653 (M −
Cl, 33%) (calcs M − Cl 880.1652).
Catalysis Experiments. For the Kinetic Study. The catalyst
(0.005 mmol) and acetophenone (0.5 mmol) were dissolved in
distilled iPrOH (4.75 mL). After a 0.1 M NaOH solution in iPrOH
(0.25 mL, 0.025 mmol) was added, the mixture was stirred at 82 °C.
At various times, aliquots were withdrawn from the sample and passed
through a short silica gel column before being analyzed by GC on a
chiral column.
ΔGsol = ΔEsol + (ΔGgas − ΔEgas
)
The energies presented in this work are given in kcal/mol.
ASSOCIATED CONTENT
■
S
* Supporting Information
For the Transfer Hydrogenation Studies. The catalyst (0.005
mmol) and acetophenone (0.5 mmol) were dissolved in distilled
iPrOH (1.25 mL). After a 0.1 M base (NaOH or KOH) solution in
iPrOH (0.25 mL, 0.025 mmol) was introduced, the mixture was stirred
at 82 °C. After 5 h, the mixture was passed through a short silica gel
column before being analyzed by GC on a chiral column.
Figures, tables, and CIF files giving optimized structures, X-ray
data, selected bond distances and angles, NMR and HR mass
spectra for all new compounds, and Cartesian coordinates for
all optimized structures. This material is available free of charge
via the Internet at http://pubs.acs.org.
For the Hydrogenation Studies. The catalyst (0.005 mmol) and
acetophenone (0.5 mmol) were dissolved in distilled iPrOH (1.25
mL) in an autoclave. After addition of a 0.1 M NaOH solution in
iPrOH (0.25 mL, 0.025 mmol), the autoclave was pressurized by H2
(30 bar). The mixture was then stirred at 50 °C. After 6 h, the
autoclave was cooled and vented and the recovered mixture was passed
AUTHOR INFORMATION
■
Corresponding Author
*E-mail: eric.deydier@iut-tlse3.fr (E.D.); eric.manoury@lcc-
toulouse.fr (E.M.).
K
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Article
(26) Labande, A.; Daran, J.-C.; Manoury, E.; Poli, R. Eur. J. Inorg.
Chem. 2007, 1205−1209.
Author Contributions
The manuscript was written through contributions of all
authors. All authors have given approval to the final version of
the manuscript.
(27) Togni, A.; Bieler, N.; Burckhardt, U.; Kollner, C.; Pioda, G.;
Schneider, R.; Schnyder, A. Pure Appl. Chem. 1999, 71, 1531−1537.
́ ́
(28) Gomez Arrayas, R.; Adrio, J.; Carretero, J. C. Angew. Chem., Int.
Notes
Ed. 2006, 45, 7674−7715.
(29) Mateus, N.; Routaboul, L.; Daran, J. C.; Manoury, E. J.
Organomet. Chem. 2006, 691, 2297−2310.
The authors declare no competing financial interest.
(30) Routaboul, L.; Vincendeau, S.; Daran, J.-C.; Manoury, E.
Tetrahedron: Asymmetry 2005, 16, 2685−2690.
ACKNOWLEDGMENTS
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(31) Audin, C.; Daran, J.-C.; Deydier, E.; Manoury, E.; Poli, R. C. R.
Chim. 2010, 13, 890−899.
We gratefully acknowledge financial support from the Centre
National de la Recherche Scientifique (CNRS), from the “Midi-
(32) Hounjel, L. J.; Bierenstiel, M.; Ferguson, M. J.; Mcdonald, R.;
Cowie, M. Inorg. Chem. 2010, 49, 4288−4300.
Pyren
the funding of Laboratoire Europee
Trans-Pyreneen: de la Molecule aux Mater
calculation at Universitat Autonoma de Barcelona.
́
ee
́
s” region, from the Institut Universitaire de France and
n Associe “Laboratoire
iaux” for the DFT
́
́
(33) Carmona, D.; Lahoz, F. J.; Elipe, S.; Oro, L. A.; Lamata, M. P.;
Viguri, F.; Sanchez, F.; Martinez, S.; Cativiela, C.; Lopez, M. P.
Organometallics 2002, 21, 5100−5114.
́
́
́
́
̀
(34) Carmona, D.; Medrano, R.; Dobrinovich, I. T.; Lahoz, F. J.;
Ferrer, J.; Oro, L. A. J. Organomet. Chem. 2006, 691, 5560−5566.
(35) Kumar, P.; Yadav, M.; Singh, A. K.; Pandey, D. S. Eur. J. Inorg.
Chem. 2010, 704−715.
(36) Altomare, A.; Burla, M.; Camalli, M.; Cascarano, G.;
Giacovazzo, C.; Guagliardi, A.; Moliterni, A.; Polidori, G.; Spagna, R.
J. Appl. Crystallogr. 1999, 32, 115−119.
(37) Sheldrick, G. M. Acta Crystallogr., Sect. A 2008, 64, 112−122.
(38) Spek, A. L. J. Appl. Crystallogr. 2003, 36, 7−13.
(39) Farrugia, L. J. J. Appl. Crystallogr. 1997, 30, 565.
REFERENCES
■
(1) Phosphorus Ligands in Asymmetric Catalysis; Borner, A., Ed.;
̈
Wiley-VCH: Weinheim, Germany, 2008; Vols. 1−3.
(2) Phosphorus Compounds: Advanced Tools in Catalysis and Material
Science; Peruzzini, M., Gonsalvi, L., Eds.; Springer: Dordrecht, The
Netherlands, 2011.
(3) Guiry, P. J.; Saunders, C. P. Adv. Synth. Catal. 2004, 346, 497−
537.
(4) Borner, A. In Phosphorus Ligands in Asymmetric Catalysis; Wiley-
̈
(40) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J. R.; Scalmani, G.; Barone, V.; Mennucci,
B.; Petersson, G. A.; Nakatsuji, H.; Caricato, M.; Li, X.; Hratchian, H.
P.; Izmaylov, A. F.; Bloino, J.; Zheng, G.; Sonnenberg, J. L.; Hada, M.;
Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima,
T.; Honda, Y.; Kitao, O.; Nakai, H.; Vreven, T.; Montgomery, J. A., Jr.;
Peralta, J. E.; Ogliaro, F.; Bearpark, M.; Heyd, J. J.; Brothers, E.; Kudin,
K. N.; Staroverov, V. N.; Kobayashi, R.; Normand, J.; Raghavachari, K.;
Rendell, A.; Burant, J. C.; Iyengar, S. S.; Tomasi, J.; Cossi, M.; Rega,
N.; Millam, N. J.; Klene, M.; Knox, J. E.; Cross, J. B.; Bakken, V.;
Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.;
Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Martin, R. L.;
Morokuma, K.; Zakrzewski, V. G.; Voth, G. A.; Salvador, P.;
VCH: Weinheim, Germany, 2008; Vol. 2, pp 549−629.
(5) Ganter, C. Chem. Soc. Rev. 2003, 32, 130−138.
(6) Brunner, H.; Kollnberger, A.; Mehmood, A.; Tsuno, T.; Zabel, M.
J. Organomet. Chem. 2004, 689, 4244−4262.
(7) Gladiali, S.; Alberico, E. Chem. Soc. Rev. 2006, 35, 226−236.
(8) Ikariya, T.; Blacker, A. J. Acc. Chem. Res. 2007, 40, 1300−1308.
(9) Wu, X. F.; Xiao, J. L. Chem. Commun. 2007, 2449−2466.
(10) Wang, C.; Wu, X. F.; Xiao, J. L. Chem. Asian J. 2008, 3, 1750−
1770.
(11) Wu, X. F.; Wang, C.; Xiao, J. L. Platinum Met. Rev. 2010, 54, 3−
19.
(12) Lundgren, R. J.; Rankin, M. A.; Mcdonald, R.; Schatte, G.;
Stradiotto, M. Angew. Chem., Int. Ed. 2007, 46, 4732−4735.
(13) Onodera, G.; Nishibayashi, Y.; Uemura, S. Angew. Chem., Int. Ed.
2006, 45, 3819−3822.
(14) Arikawa, Y.; Ueoka, M.; Matoba, K.; Nishibayashi, Y.; Hidai, M.;
Uemura, S. J. Organomet. Chem. 1999, 572, 163−168.
(15) Nishibayashi, Y.; Takei, I.; Uemura, S.; Hidai, M. Organo-
metallics 1999, 18, 2291−2293.
(16) Hounjet, L. J.; Ferguson, M. J.; Cowie, M. Organometallics 2011,
30, 4108−4114.
(17) Bacchi, A.; Balordi, M.; Cammi, R.; Elviri, L.; Pelizzi, C.;
Picchioni, F.; Verdolino, V.; Goubitz, K.; Peschar, R.; Pelagatti, P. Eur.
J. Inorg. Chem. 2008, 4462−4473.
(18) Dahlenburg, L.; Kuhnlein, C. J. Organomet. Chem. 2005, 690, 1−
13.
̈
Dannenberg, J. J.; Dapprich, S.; Daniels, A. D.; Farkas, O.;
Foresman, J. B.; Ortiz, J. V.; Cioslowski, J.; Fox, D. J. Gaussian 09,
Revision A.01; Gaussian, Inc., Wallingford, CT, 2009.
(41) Hay, P. J.; Wadt, W. R. J. Chem. Phys. 1985, 82, 270−283.
(42) Hay, P. J.; Wadt, W. R. J. Chem. Phys. 1985, 82, 299−310.
(43) Ehlers, A. W.; Boehme, M.; Dapprich, S.; Gobbi, A.; Hoellwarth,
A.; Jonas, V.; Koehler, K. F.; Stegmann, R.; Veldkamp, A.; Frenking, G.
Chem. Phys. Lett. 1993, 208, 111−114.
(44) Marenich, A. V.; Cramer, C. J.; Truhlar, D. G. J. Phys. Chem. B
2009, 113, 6378−6396.
(45) Hayashi, T.; Mise, T.; Fukushima, M.; Kagotani, M.; Nagashima,
N.; Hamada, Y.; Matsumoto, A.; Kawakami, S.; Konishi, M.;
Yamamoto, K.; Kumada, M. Bull. Chem. Soc. Jpn. 1980, 53, 1138−
1151.
(19) Madrigal, C. A.; Garcia-Fernandez, A.; Gimeno, J.; Lastra, E. J.
Organomet. Chem. 2008, 693, 2535−2540.
(20) Braunstein, P.; Graiff, C.; Naud, F.; Pfaltz, A.; Tiripicchio, A.
Inorg. Chem. 2000, 39, 4468−4475.
(21) Manoury, E.; Fossey, J.; Ait-Haddou, H.; Daran, J.; Balavoine, G.
Organometallics 2000, 19, 3736−3739.
(22) Mourgues, S.; Serra, D.; Lamy, F.; Vincendeau, S.; Daran, J.;
Manoury, E.; Gouygou, M. Eur. J. Inorg. Chem. 2003, 2820−2826.
(23) Lopez Cortes, J. G.; Ramon, O.; Vincendeau, S.; Serra, D.;
Lamy, F.; Daran, J. C.; Manoury, E.; Gouygou, M. Eur. J. Inorg. Chem.
2006, 5148−5157.
(24) Routaboul, L.; Vincendeau, S.; Turrin, C. O.; Caminade, A. M.;
Majoral, J. P.; Daran, J. C.; Manoury, E. J. Organomet. Chem. 2007,
692, 1064−1073.
(25) Le Roux, E.; Malacea, R.; Manoury, E.; Poli, R.; Gonsalvi, L.;
Peruzzini, M. Adv. Synth. Catal. 2007, 349, 309−313.
L
dx.doi.org/10.1021/om300738q | Organometallics XXXX, XXX, XXX−XXX